Power-driven hacksaw.



T. RAE.

POWER DRIVEN HAcKsAw,

APPLICATION FILED NOV.20, |916.

Patented Oct. 15, i918 2 SHEETS-SHEET l.

mman, a. c.

T. RAE.'

POWER DRIVEN HACKSAW.

APPLICATION HLED Nov.'2o. 1916.

atented 0ct.15,1918.

2 SHEETS-SHEET 2.

YZ (J2/lag' (BJ ym 720% THOMAS RAE, OF SYDNEY, NEW SOUTH WALES,AUSTRALIA.

POWER-DRIVEN HACKSAW.

Specification of Letters Patent.

raeentea oct. i5, i918.

Application filed November 20, 1916.V Serial N o. 132,456.

To all whom t may concern:

Be it known that I, THOMAS RAE, subject fof the King of Great Britain,residing at Sydney, New South Wales, Commonwealth of Australia, haveinvented new and useful Improvements in Power-Driven Hacksaws, of whichthe following is a specification.

This invention relates to improvements in power driven hack-saws thatare provided with automatically controlled lifting devices for raisingthe saw on its return or noncutting stroke and it has for its object theprovision of simple and easily controlled means whereby such saws willhave greater efficiency in use.

The invention is directed more particularly to the means devised forlifting the saw from the work at the completion of the cutting strokeand returning it correctly to the work at the completion of itsnon-cutting stroke. The invention furthermore embodies novel features ofconstruction whereby the operative parts canbe readily adjusted to suitthe particular requirements of the work to be performed.

In order that the invention may be readily understood reference will nowbe had to the accompanying sheets of explanatory drawings, wherein-Figure l is a View in perspective of a power hack-saw ymachineconstructed in accordance with the invention, part of the frame workbeing shown broken away for convenience of illustration.

Fig. 2 is a view in perspective of the power driven hack-saw shown inFig. 1 viewed from the rear side of the machine.

Fig. 3 is a view in side elevation of the operative parts of theinvention, part being shown in sectional elevation.

Fig. 4 is a view in end elevation of a friction gripping device thatforms part of the means devisedfor lifting the saw from the work at thecompletion of its cutting stroke.

Fig. 5 is a view in sectional plan taken on the line 5-5 of Fig. 4.

Fig. 6 is a view in cross section taken on the dotted line 6-6 of partof Fig. 6 and drawn to a larger scale than the other views.

Fig. 7 isa view in side elevation (partly in section) of a device forreleasing the gripping device shown in Figs. 4 and 5.

In these drawings like characters of reference have been employed toindicate similar or corresponding parts in the different views and thenumeral l designates a frame upon one end of which is mounted arevoluble shaft 2. The shaft 2 is mounted transversely on one end of theframe 1 and is fitted with a cam 3, a belt pulley 4 and a crank disk 5.

An arm 6 is pivoted to a sleeve (not shown) on the shaft 2 and said armprojects toward the opposite end of the frame, and is designed tosupport a saw carrying bow 7 The said saw-bow 7 is connected by a link 7to a pin 9 formed on or fitted to the crank disk 5.

The back of the saw-bow 7 is slotted out at 10 on one side to fit overthe curved outer end of the arm 6 and the bow is retained on said arm bymeans of a plate 11. rIhe plate 11 is bolted orotherwise secured to theback of the saw-bow and removable and adjustable wearing strips 12 areprovided to take up all wear incident to the bow reciprocating on thearm. Y

The guide slot 10 and curved portion of the arm 6 curve downwardly in agradual sweep from each end and forms a long bearing that obviates theslightest vibration. The radial draw motion obtained by the sweep of thecurved guide provides for a maximum cutting efficiency with a minimum ofpressure and friction as only a few of the saw teeth are kept in touchwith thevwork.

One end of the saw-bow is fitted with an yadjustable blade holder 13 andthe opposite end of the said saw-bow is provided with a pin 14 that isengaged by a hole in the saw blade 15 in the ordinary way.

The saw-bow is raised slightly when the saw has completed its cuttingstroke and is kept in its raised positionuntil it has furnished itsoutward or idle stroke when it is again lowered on to the work. 1

The saw-bow is raised by the action of the cam 3 and a lever 16 theformer being timed to effect the movements ,above described. The cam 3bears against the underside of a roller 17 carried on the lever 16 andthe outer end of said lever is pivoted to a bracket 18 on the frame 1.rlhe inner end of the lever 16 is provided with a frictional grippingmember that engages a curved bar 19 depending from the saw carrying arm6.

The forward end of the lever 16 is enlarged and bifurcated to fit aroundthe curved bar 19 and the sides 20 of the bifurcation are inclineddownwardly as shown in Fig. 4 of the drawings.

The inclined sides of the bifurcation in the end of the lever 16 arefitted with steel plates 21 and rollers 22 are arranged horizontallybetween the plates 21 and the curved bar 19.

The rollers 22 are supported between the enlarged ends of oppositelydisposed spindles 23 and 24 that are reciprocatingly mounted in top andbottom cover-plates 25 and 26 respectively, fitted to the bifurcated endof the lever 16.

The rollers, normally, are pressed downward by the action of compressionsprings 27 fitted to the spindles 23. The cover-plates 25 and 26 aresecurely fastened to the inner end-of the lever by means of bolts 28. Afront cover-plate 29 is fitted to the inner end of the lever 16 by meansof screws 30 to completely house the rollers 22 and insure them beingretained in their correct operative positions.

When the outer end of the lever 16 is loweredv the lower ends of thebottom spindles 24 are brought to bear upon tappets 31 that cause saidspindles 24 to rise and release the rollers 22 at the completion of eachreturn or idle stroke and thereby enable the saw to drop slightly totake the cut.

The tappets 31 screw into sleeves 32 for purposes of adjustment and thesaid sleeves are free to rise and fall in a supporting bracket33 fittedto the machine frame. A lever 34 pivoted on the bracket 33 is arrangedto raise the tap'pets 31 by hand to free the gripping rollers 22 andenable the saw to be loweredinto position on the work at thecommencement of operations.

In order to prevent the saw-bow from dropping too rapidly andendangering the parts-as in the event of a saw breaking-a dash potcomprising an ordinary cylinder 35 is located beneath the frame. Apiston 36 is fitted in the cylinder 35 and is adapted to rise freely andbe retarded on the down stroke.

The upper end of a piston rod 37 is formed with a laterally projectingpin 38 that is loosely engaged by a'slot 39 formed in the lower end of arod 40 having its upper end ivoted to the arm 6. The slot 39 isslightlyonger than the clearance lift of the saw so that said saw may drop toeach successive cut in vadvance Vof the' slowly descending piston. y

The lever 16 is provided with an adjustable rod 41 to the lower end ofwhich is connected one end of a tension spring 42 the The machineisfitted with a-"vise 48v to hold the material to be cut and a gage 49to determine the length to be cut from a bar of metal orV the like.vided to prevent the severed portion of a rod or bar coming intoforcible contact with the saw and damaging it. l

lNhen the saw has reached its lowest position after cutting through abar or the like, the inner end of the bow comes into contact withandoperates a lever 51 that is connected to a clutch (not shown) on theshaft. The clutch can be put vinto or out of gear in the ordinary way byoperating a hand lever 52.

The base of the frame is made hollow to contain a liquid that will actas a lubricant andV keep the saw cool when in operation. A small pump 53is provided to force the liquid from the base of theframe through a pipe54 to a flexible pipe 55 that directs the liquid on t0 the saw andmaterialrbeing cut by the Guide pins 50 are pro-'V same. The pump 53 isdriven by belt and pulley mechanism 56 from the shaft 2.

Y rlfhe liquid sprayed on to the saw by the pipe 55 flows into a channel57 formed around the frame of the machine and it is directedfrom saidchannel through an opening 58 back to'the hollow base of the machine.

The invention is extremely simple in construction and operation and inuse Awill be found thoroughly efficient for the purpose for which it hasbeen devised.

What 1 do claim is 1. A power hack-saw comprising a frame, a revolubleshaft mounted( transversely on the frame, an arm pivoted at one end onthe shaft, a saw-bow reciprocatingly mounted on the pivoted` arm, Vacrank disk on the shaft, a link connecting the crankdisk to the saw-bow,a bracket on one end-of the frame, a lever pivoted to the bracket, aroller on the lever, a cam fitted to the shaft and bearing on theunder-side of the roller, a curved bar fitted to'and depending from thepivoted arm, -an enlarged inner end on the lever, a mortise. in theenlarged end of the lever to accommodate the curved bar, frictiongripping devices located within the enlarged end of the lever to engagethe curvedv bar, and means for releasing the friction grippin devices,substantially as described.

2. In4 a power hack-saw, a frame, a hori- Zontal shaft, a pivoted arm, asaw-bow reciprocatingly mounted on the arm, a lever pivoted at one endto the frame, a mortise in the free end of the lever having inclinedsides, a curved bar depending from thepivoted arm and passing throughthe mortise in the lever, rollers between the sides kof the curved barand the inclined sides of the mortise, spindles having enlarged headssuperting a downward pressure on the rollers,

bar depending from the pivoted arm and engaged by the friction grippingdevice, a roller on the lever, a cam on the shaft bearing against theunderside of the roller, and means for intermittently releasing thefriction gripping device, substantially as de-` scribed. K

4. In a power hack-saw, a frame, a horizontal shaft mounted transverselyon the frame, an arm pivoted at one end, a sawbow reciprocatinglymounted on the free end of the arm, a bracket on the frame, a leverpivoted at one end to the bracket, means for raising and lowering thefree end of the lever, a vertical mortise in the free end of the leverhaving inclined sides, wear ing plates fitted to the inclined sides ofthe mortise, a curved bar depending from the pivoted arm and passingthrough the mortise in the lever, rollers located between the sides ofthe curved bar and the sides of the mortise, spindles arrangedvertically7 above and below the rollers to support the same within themortise, springs exerting a downward pressure on the rollers, andadjustable tappets beneath the lower spindles,

substantially as described.

5. In a power hack-saw, a pivoted arm carrying a reciprocatingly mountedsawbow, a pivoted lever having a vertical mortise therein formed withinclined sides, a curved bar depending from the pivoted arm and passingthrough the mortise, rollers in the mortise, vertical spindlessupporting the rollers, adjustable tappets located beneath the spindles,a pivoted lever supporting the tappets, and a bracket supporting thetappet supporting lever, substantially as described.

6. In a power hack-saw, a pivoted arm carrying a reciprocatingly mountedsawbow, a saw on said saw-bow, a curved bar depending from the pivoted.arm, a pivoted lever having a vertical mortise therein formed withinclined sides, a pair of rollers in the mortise arranged to engage thecurved bar .on the pivoted arm, means for raising and lowering the leverand means for throwing the rollers out of engagement with the curved barwhile the saw is moving on its working stroke, substantially asdescribed.

7. In a power hack-saw, a frame, a shaft revolubly mounted on the frame,a pivoted arm, a saw-bow reciprocatingly mounted on the arm, weightsadjustably secured to the pivoted arm, a bracket on one end of theframe, a lever pivoted at one end to the bracket, a roller on saidlever, a cam fitted to the shaft and bearing against the underside ofthe roller, a friction gripping device on the free end of the lever acurved bar depending from the pivoted arm and passing through thegripping device, a crank on the shaft, a link connecting the crank tothe sawbow, a cylinder fitted to the frame, apiston in the cylinder, arod having its lower end loosely connected to the piston and its upperend pivoted to the pivoted arm, and a spring connection between thelever and the frame, substantially as described.

8. In a power hack-saw, a frame, a shaft mounted transversely on theframe, an arm `having' one end pivoted to the shaft and the opposite endformed with aI regular downward curve, a saw-bow having a curved recesssiidably engaging the curved part of the pivoted arm, means on thesaw-bow for detachably securing a saw thereto, weights securedadjustably to the pivoted arm, al

bracket on one end of the frame, a lever having one end pivoted to thebracket and its opposite end provided with a friction gripping device, aroller on the lever, a curved bar depending from the pivoted arm andengaged by the gripping device, a cam on the shaft arranged to bearagainst the underside of the roller on the lever and a crank on theshaft operatively connected to the saw-bow, substantially as described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

THOMAS RAE. Witnesses:

M. C. KENNEDY, W. STARFIELD.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. C.

